A number of disease states result in some degree of contamination of cerebrospinal fluid (CSF). The skilled reader will recall that the brain and the spinal chord reside within the cranium and the spinal column respectively. Both the brain and the spinal column of the human central nervous system (CNS) are exquisitely delicate and therefore are surrounded by cerebrospinal fluid (CSF) in both the cranium and the spinal column. Further, the brain itself includes passages and sinuses which are also filled with CSF. The CSF of a normal, healthy patient is typically very pure and typically free of blood cells, foreign particles, pathogens, bacteria or any other form of contaminant. Several disease states may disrupt or compromise the purity of CSF. Two examples include meningitis and hemorrhagic stroke.
Meningitis is an inflammation of the membranes surrounding the brain and the spinal cord which are collectively known as the meninges. Frequently, such an inflammation is caused by a bacterial infection. Accordingly, in common parlance, the term “meningitis” is often used as a general term to refer to such an infection. As such, meningitis can be indicative of an extremely dangerous and potentially fatal infection. For this reason, a meningitis infection is considered to be an emergency condition. The early detection and treatment of meningitis is of the utmost importance if there is to be a positive outcome for a patient. The present standard of care in the diagnosis of meningitis includes the insertion of a needle into the spinal column between two vertebrae and the extraction of CSF. The act of inserting a needle for extracting CSF is also referred to as a “lumbar puncture”. Once CSF is extracted, it is tested using agar plate testing to identify an infecting agent. This process can take up to 72 hours and the test will yield a negative result unless there is a significant presence of an infecting organism. Once a diagnosis is made, rapid and aggressive treatment is vital for improving the patient's outcome. Any delay in the inception of treatment increases the risk of neurological complications including: impaired mental status, increased intra-cranial pressure, cerebral edema, seizures, cerebrovascular abnormalities, hearing loss, intellectual impairment, and death. A method that offers an immediate diagnosis of meningitis would improve patient outcomes and would also provide a contraindication in performing a risky lumbar puncture for the extraction of CSF. The complications that can occur as a result of lumbar punctures are not trivial. They include post-lumbar puncture headache which occurs in up to 40% of patients, short or long term back discomfort or pain, bleeding into epidural space, brainstem herniation, paraplegia, infection, and even though very rare, death.
At an early stage, meningitis resembles influenza, making initial diagnosis difficult without the classical symptom of nuchal rigidity (a stiff neck). An early missed diagnosis results in the loss of the early critical treatment period. What is needed is a non-invasive, reliable test for determining if a patient has meningitis.
A hemorrhagic stroke is a condition wherein an artery associated with supplying blood to the brain ruptures. A hemorrhagic stroke can occur when an artery supplying blood to the brain harbors an aneurysm. Such ruptures very often result in blood being released into the CSF. This in turn causes the CSF to be contaminated with blood cells and other blood constituents. A significant concern in the early diagnosis of a stroke is to distinguish a hemorrhagic stroke from an ischemic stroke. Recall that ischemic strokes result from a blood clot in the brain. Ischemic strokes are generally not accompanied by the release of blood into the CSF. The importance of distinguishing between hemorrhagic strokes and ischemic strokes is related to the initial therapy often administered to ischemic stroke patients. Such initial therapy often includes the administration of drugs which are directed toward breaking up blood clots. The administration of such drugs in the case of a hemorrhagic stroke would most likely aggravate the intra-cranial bleeding and harm the patient. Accordingly, what is needed is a means for quickly distinguishing between an ischemic and a hemorrhagic stroke.